Action of carbamazepine on epileptiform activity of the verartidine model in CA1 neurons.

The veratridine epileptiform model was utilized to assess the antiepileptic effect of Carbamazepine (CBZ) in rat hippocampal CA1 pyramidal neurons using conventional intracellular recording techniques. In the veratridine model, where brain slices are treated with veratridine (0.3 microM), a single intracellular stimulus evokes epileptiform bursting. Additionally, spontaneous epileptiform activity commonly appears on prolonged exposure to veratridine in this model. In this model, therapeutic (7-15 microM) and high (50 microM) concentrations of CBZ inhibited the evoked and spontaneous epileptiform bursting in a concentration- and voltage-dependent manner. At all concentrations tested, CBZ produced inhibition of epileptiform activity without affecting the membrane resting potential or input resistance. However, at 50 microM, the drug increased the firing threshold of neurons. These results confirm the suitability of this model for testing sodium channel-dependent antiepileptic agents.